Heterogeneous Optimization Strategies for Carved and Squealer-Like Turbine Blade Tips

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua ◽  
T. Verstraete ◽  
R. Olive ◽  
...  
Keyword(s):  
Rotor Blades ◽  
Optimization Process ◽  
Navier Stokes ◽  
Optimization Strategy ◽  
Design Strategies ◽  
Multi Objective ◽  
Sst Turbulence Model ◽  
Blade Tip ◽  
Optimization Routine ◽  
Level Set Approach

Superior rotor tip geometries possess the potential to simultaneously mitigate aerodynamic losses and severe thermal loads onto the rotor overtip region. However, classical design strategies are usually constrained to a specific type of geometry, narrowing the spread of shape topologies considered during the design phase. The current paper presents two novel multi-objective optimization methodologies that enable the exploration of a broad range of distinct tip configurations for unshrouded rotor blades. The first methodology is a shape optimization process that creates a fully carved blade tip shape defined through a Bezier surface controlled by 40 parameters. Combined with a differential evolution (DE) optimization strategy, this approach is applied to a rotor blade for two tip gap sizes: 0.85% (tight) and 1.38% (design) of the blade span. The second methodology is based on a topology optimization process that targets the creation of arbitrary tip shapes comprising one or multiple rims with a fixed height. The tip section of the blade has been divided into more than 200 separate zones, where each zone can be either part of an upstanding rim or part of the cavity floor. This methodology was tested with a level-set approach in combination with a DE optimizer and coupled to an optimization routine based on genetic algorithms (GAs). The current study was carried out on a modern high-pressure turbine operating at engine-like Reynolds and high subsonic outlet Mach numbers. A fully hexahedral unstructured mesh was used to discretize the fluid domain. The aerothermal performance of each tip profile was evaluated accurately through Reynolds-averaged Navier–Stokes (RANS) simulations adopting the shear-stress transport (SST) turbulence model. Multi-objective optimizations were set for both design strategies that target higher aerodynamic rotor efficiencies and simultaneous minimization of the heat load. This paper illustrates a wide variety of profiles obtained throughout the optimization and compares the performance of the different strategies. The research shows the potential of such novel methodologies to reach new unexplored types of blade tip designs with enhanced aerothermal performances.

Heterogeneous Optimization Strategies for Carved and Squealer-Like Turbine Blade Tips

2015 ◽  
Author(s):  
C. De Maesschalck ◽  
S. Lavagnoli ◽  
G. Paniagua ◽  
T. Verstraete ◽  
R. Olive ◽  
...  
Keyword(s):  
Differential Evolution ◽  
Rotor Blades ◽  
Optimization Process ◽  
Optimization Strategy ◽  
Design Strategies ◽  
Multi Objective ◽  
Sst Turbulence Model ◽  
Blade Tip ◽  
Optimization Routine ◽  
Level Set Approach

Superior rotor tip geometries possess the potential to simultaneously mitigate aerodynamic losses and severe thermal loads onto the rotor overtip region. However, classical design strategies are usually constrained to a specific type of geometry, narrowing the spread of shape topologies considered during the design phase. The current paper presents two novel multi-objective optimization methodologies that enable the exploration of a broad range of distinct tip configurations for unshrouded rotor blades. The first methodology is a shape optimization process that creates a fully carved blade tip shape defined through a Bezier surface controlled by 40 parameters. Combined with a differential evolution optimization strategy, this approach is applied to a rotor blade for two tip gap sizes: 0.85% (tight) and 1.38% (design) of the blade span. The second methodology is based on a topology optimization process that targets the creation of arbitrary tip shapes comprising one or multiple rims with a fixed height. The tip section of the blade has been divided into more than 200 separate zones, where each zone can be either part of an upstanding rim or part of the cavity floor. This methodology was tested with a level-set approach in combination with a differential evolution optimizer, and coupled to an optimization routine based on genetic algorithms. The current study was carried out on a modern high-pressure turbine operating at engine-like Reynolds and high subsonic outlet Mach numbers. A fully hexahedral unstructured mesh was used to discretize the fluid domain. The aerothermal performance of each tip profile was evaluated accurately through RANS simulations adopting the SST turbulence model. Multi-objective optimizations were set for both design strategies that target higher aerodynamic rotor efficiencies and simultaneous minimization of the heat load. This paper illustrates a wide variety of profiles obtained throughout the optimization and compares the performance of the different strategies. The research shows the potential of such novel methodologies to reach new unexplored types of blade tip designs with enhanced aerothermal performances.

Aerothermal Optimization of Fully Cooled Turbine Blade Tips

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Valeria Andreoli ◽  
James Braun ◽  
Guillermo Paniagua ◽  
Cis De Maesschalck ◽  
Matthew Bloxham ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Heat Load ◽  
Performance Enhancement ◽  
Navier Stokes ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Hexahedral Elements ◽  
Sst Model ◽  
Blade Tip ◽  
Novel Strategy

Optimal turbine blade tip designs have the potential to enhance aerodynamic performance while reducing the thermal loads on one of the most vulnerable parts of the gas turbine. This paper describes a novel strategy to perform a multi-objective optimization of the tip geometry of a cooled turbine blade. The parameterization strategy generates arbitrary rim shapes around the coolant holes on the blade tip. The tip geometry performance is assessed using steady Reynolds-averaged Navier–Stokes simulations with the k–ω shear stress transport (SST) model for the turbulence closure. The fluid domain is discretized with hexahedral elements, and the entire optimization is performed using identical mesh characteristics in all simulations. This is done to ensure an adequate comparison among all investigated designs. Isothermal walls were imposed at engine-representative levels to compute the convective heat flux for each case. The optimization objectives were a reduction in heat load and an increase in turbine row efficiency. The multi-objective optimization is performed using a differential evolution strategy. Improvements were achieved in both the aerodynamic efficiency and heat load reduction, relative to a conventional squealer tip arrangement. Furthermore, this work demonstrates that the inclusion of over-tip coolant flows impacts the over-tip flow field, and that the rim–coolant interaction can be used to create a synergistic performance enhancement.

Aerothermal Optimization of Fully Cooled Turbine Blade Tips

2018 ◽  
Author(s):  
V. Andreoli ◽  
J. Braun ◽  
G. Paniagua ◽  
C. De Maesschalck ◽  
M. Bloxham ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Heat Load ◽  
Performance Enhancement ◽  
Navier Stokes ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Hexahedral Elements ◽  
Sst Model ◽  
Blade Tip ◽  
Novel Strategy

Optimal turbine blade tip designs have the potential to enhance aerodynamic performance while reducing the thermal loads on one of the most vulnerable parts of the gas turbine. This paper describes a novel strategy to perform a multi-objective optimization of the tip geometry of a cooled turbine blade. The parameterization strategy generates arbitrary rim shapes around the coolant holes on the blade tip. The tip geometry performance is assessed using steady Reynolds-Averaged Navier-Stokes simulations with the k-ω SST model for the turbulence closure. The fluid domain is discretized with hexahedral elements, and the entire optimization is performed using identical mesh characteristics in all simulations. This is done to ensure an adequate comparison among all investigated designs. Isothermal walls were imposed at engine-representative levels to compute the convective heat flux for each case. The optimization objectives were a reduction in heat load and an increase in turbine row efficiency. The multi-objective optimization is performed using a differential evolution strategy. Improvements were achieved in both the aerodynamic efficiency and heat load reduction, relative to a conventional squealer tip arrangement. Furthermore, this work demonstrates that the inclusion of over-tip coolant flows impacts the over-tip flow field, and that the rim-coolant interaction can be used to create a synergistic performance enhancement.

scholarly journals Multi-Objective Optimization in Axial Compressor Design Using a Linked CFD-Solver

2008 ◽  
Author(s):  
Kai Becker ◽  
Martin Lawerenz ◽  
Christian Voß ◽  
Reinhard Mo¨nig
Keyword(s):  
Guide Vane ◽  
Axial Compressor ◽  
Navier Stokes ◽  
Inlet Guide Vane ◽  
Optimization Strategy ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Flow Information ◽  
Design Variation

In combination with a multi-objective 3D optimization strategy, a linked CFD-solver is presented in this paper, combining 3D-Reynolds-averaged-Navier-Stokes and an inviscid throughflow method. It enables the adjustment of the 3D boundary conditions for any design variation and contains new options for configuring the objective functions. The link is achieved by matching the flow information between both CFD codes in an iterative procedure. Compared to an individual 3D-CFD calculation, the convergence does not take significantly longer. The potential of the linked CFD-solver is demonstrated in a multi-objective optimization for one blade row to be optimized and one operating point at a 3-stage axial compressor with inlet guide vane. Within the optimization, the objective functions are formulated, so that the performance of the axial compressor is enhanced in addition to the improved efficiency of the 3D-cascade.

Tip Leakage/Main Flow Interactions in Multi-Stage HP Turbines With Short-Height Blading

2004 ◽  
Author(s):  
Piotr Lampart ◽  
Sergey Yershov ◽  
Andrey Rusanov ◽  
Mariusz Szymaniak
Keyword(s):  
Labyrinth Seal ◽  
Main Flow ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Blade Passage ◽  
Tip Leakage ◽  
Multi Stage ◽  
Flow Interactions ◽  
Sst Turbulence Model ◽  
Downstream Flow

Interaction of the main flow with tip leakage over shrouded rotor blades in a multi-stage turbine is studied numerically. The flow in blade-to-blade channels is computed with the aid of a 3D Navier-Stokes solver FlowER with the Menter SST turbulence model. In this paper, the labyrinth seals are not computed but the numerical scheme is modified to include the source/sink-type boundary conditions at places at the endwalls referring to design locations of injection of leakage flows into, or their extraction from, the blade-to-blade passage. Without considering complete labyrinth seal geometries, the tip leakage jet is represented by its flow rate and direction at re-entry to the blade-to-blade passage, as if referring to the performance of a range of different labyrinth seal arrangements. The effect of direction of tip leakage re-entry on the downstream flow and efficiency of the turbine stage (stage group) is studied. The calculation method is validated on a model air stator/rotor turbine.

scholarly journals Pipe route optimization to avoid undesired vibration by using JuliaFEM

2019 ◽  
Vol 52 (3) ◽  
pp. 177-191 ◽  
Author(s):  
Marja Rapo ◽  
Joona Vaara ◽  
Teemu Kuivaniemi ◽  
Niclas Liljenfeldt ◽  
Antti Vuohijoki ◽  
...  
Keyword(s):  
Finite Element Method ◽  
High Pressure ◽  
Route Optimization ◽  
Optimization Process ◽  
Quick Response ◽  
Optimization Strategy ◽  
Development Environment ◽  
Optimization Routine ◽  
High Level ◽  
Embedded Implementation

An optimization routine was applied to high pressure fuel pipes to avoid resonance in a heavily vibrating environment. The optimization process and also the natural frequency calculations in every iteration were completely performed with the high-level programming language Julia; the optimization process was performed with the JuMP optimization environment, and the frequencies where calculated with JuliaFEM finite element method solver platform. The benefit of this kind of embedded implementation is a quick response which yields a pleasant development environment to focus on the essential—the choice of the optimization strategy.

scholarly journals Optimization strategy of wireless charger node deployment based on improved cuckoo search algorithm

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Yang Wang ◽  
Feifan Wang ◽  
Yujun Zhu ◽  
Yiyang Liu ◽  
Chuanxin Zhao
Keyword(s):  
Sensor Network ◽  
Sensor Node ◽  
Search Algorithm ◽  
Optimal Solution ◽  
Cuckoo Search ◽  
Cuckoo Search Algorithm ◽  
Sensor Nodes ◽  
Optimization Strategy ◽  
Multi Objective ◽  
Received Power

AbstractIn wireless rechargeable sensor network, the deployment of charger node directly affects the overall charging utility of sensor network. Aiming at this problem, this paper abstracts the charger deployment problem as a multi-objective optimization problem that maximizes the received power of sensor nodes and minimizes the number of charger nodes. First, a network model that maximizes the sensor node received power and minimizes the number of charger nodes is constructed. Second, an improved cuckoo search (ICS) algorithm is proposed. This algorithm is based on the traditional cuckoo search algorithm (CS) to redefine its step factor, and then use the mutation factor to change the nesting position of the host bird to update the bird’s nest position, and then use ICS to find the ones that maximize the received power of the sensor node and minimize the number of charger nodes optimal solution. Compared with the traditional cuckoo search algorithm and multi-objective particle swarm optimization algorithm, the simulation results show that the algorithm can effectively increase the receiving power of sensor nodes, reduce the number of charger nodes and find the optimal solution to meet the conditions, so as to maximize the network charging utility.

scholarly journals Effect of in-service burnout effect on the transonic leakage flows over cavity tip model

2021 ◽  
pp. 095765092110121
Author(s):  
Zainab J Saleh ◽  
Eldad J Avital ◽  
Theodosios Korakianitis
Keyword(s):  
Turbine Blades ◽  
High Heat ◽  
Navier Stokes ◽  
Gas Temperature ◽  
Flow Measurements ◽  
Tip Leakage ◽  
Leakage Flows ◽  
Operational Life ◽  
Flow Interactions ◽  
Blade Tip

Increasing the gas temperature at the inlet to the high pressure turbine of gas turbine engines is known as a proven method to increase the efficiency of these engines. However, this will expose the blades’ surface to very high heat load and thermal damages. In the case of the un-shrouded turbine blades, the blade tip will be exposed to a significant thermal load due to the developed leakage flows in the tip gap, this leads to in-service burnout which degrades the blade tip and shortens its operational life. This paper studies the in-service burnout effect of the transonic tip flows over a cavity tip which is a configuration commonly used to reduce the tip leakage flows. This investigation is carried out experimentally within a transonic wind tunnel and computationally using steady and unsteady Reynolds Averaged Navier Stokes approaches. Various flow measurements are established and different flow behaviour including separation bubbles, shockwave development and distinct flow interactions are captured and discussed. It is found that when the tip is exposed to the in-service burnout, leakage flow behaves in a significantly different way. In addition, the effective tip gap becomes much larger and allows higher leakage mass flow rate in comparison to the sharp-edge tip (i.e. a tip at the beginning of its operational life). The tip leakage losses are found much higher for the round-edge cavity tip (i.e. a tip exposed to burn-out effect). Experimental and computational flow visualisations, surface pressure measurements and discharge coefficient variation are given and analysed for several pressure ratios across the tip gap.

scholarly journals Design-Assisted of Pitching Aerofoils through Enhanced Identification of Coherent Flow Structures

Designs ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 11 ◽  
Author(s):  
Filippo Avanzi ◽  
Francesco De Vanna ◽  
Yin Ruan ◽  
Ernesto Benini
Keyword(s):  
Pressure Field ◽  
Navier Stokes ◽  
Flow Structures ◽  
Coupled Modes ◽  
Spectral Reconstruction ◽  
Sst Turbulence Model ◽  
Coherent Flow Structures ◽  
Highly Correlated ◽  
Naca 0012 ◽  
Proper Orthogonal

This study discusses a general framework to identify the unsteady features of a flow past an oscillating aerofoil in deep dynamic stall conditions. In particular, the work aims at demonstrating the advantages for the design process of the Spectral Proper Orthogonal Decomposition in accurately producing reliable reduced models of CFD systems and comparing this technique with standard snapshot-based models. Reynolds-Averaged Navier-Stokes system of equations, coupled with k−ω SST turbulence model, is used to produce the dataset, the latter consisting of a two-dimensional NACA 0012 aerofoil in the pitching motion. Modal analysis is performed on both velocity and pressure fields showing that, for vectored values, a proper tuning of the filtering process allows for better results compared to snapshot formulations and extract highly correlated coherent flow structures otherwise undetected. Wider filters, in particular, produce enhanced coherence without affecting the typical frequency response of the coupled modes. Conversely, the pressure field decomposition is drastically affected by the windowing properties. In conclusion, the low-order spectral reconstruction of the pressure field allows for an excellent prediction of aerodynamic loads. Moreover, the analysis shows that snapshot-based models better perform on the CFD values during the pitching cycle, while spectral-based methods better fit the loads’ fluctuations.

URANS Studies of Effect of Eccentricity on Ship–Lock Interactions

2016 ◽  
Vol 13 (04) ◽  
pp. 1641012
Author(s):  
Qingjie Meng ◽  
Decheng Wan
Keyword(s):  
Viscous Flow ◽  
Hydrodynamic Interaction ◽  
Vertical Displacement ◽  
Navier Stokes ◽  
Test Case ◽  
The Third ◽  
Surface Pressure Distribution ◽  
Sst Turbulence Model ◽  
Unsteady Viscous Flow ◽  
Ship Lock

The unsteady viscous flow around a 12000TEU ship model entering the Third Set of Panama Locks with different eccentricity is simulated by solving the unsteady Reynolds averaged Navier–Stokes (RANS) equations in combination with the [Formula: see text]SST turbulence model. Overset grid technology is utilized to maintain grid orthogonality and the effects of the free surface are taken into account. The hydrodynamic forces, vertical displacement as well as surface pressure distribution are predicted and analyzed. First, a benchmark test case is designed to validate the capability of the present methods in the prediction of the viscous flow around the ship when maneuvering into the lock. The accumulation of water in front of the ship during entry into a lock is noticed. A set of systematic computations with different eccentricity are then carried out to examine the effect of eccentricity on the ship–lock hydrodynamic interaction.

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